中华绒螯蟹一龄早熟和二龄成熟家系生长规律的比较研究

中华绒螯蟹(Eridcheir sinensis)1龄性早熟是扣蟹养殖过程中的一个重要问题,尚不清楚1龄性早熟和2龄正常性成熟后代的生长发育规律是否存在差异,本研究通过构建1龄性早熟和正常性成熟中华绒螯蟹家系,综合比较了单养条件下两种家系子一代(以下简称早熟F1和正常F1)在扣蟹和成蟹阶段的生长蜕壳规律、雌蟹腹脐覆盖腹甲宽度比例、成熟后的性腺指数(GSI)和肝胰腺指数(HSI)。结果显示:(1)早熟F1雄体在第1、2次和第7、8次蜕壳后的体重显著大于正常F1雄体(P0.05);而早熟F1雌体在第1~5次和第7次蜕壳后的体重显著大于正常F1雌体(P0.05);(2)第1和2次蜕壳后早熟F1的增重率较高,正常F1在第3~8次蜕壳后的增重率略高于早熟F1,两群体在扣蟹阶段的特定生长率均呈下降趋势,且正常F1高于早熟F1,其中雌雄个体在第3~4次蜕壳后的特定生长率均存在显著差异(P0.05);(3)早熟F1在第1~5次蜕壳间隔较长,而第6~8次蜕壳间隔较短;两种家系在扣蟹养殖阶段蜕壳4~6次,成蟹养殖阶段蜕壳2~4次,其中早熟F1在扣蟹阶段的平均蜕壳次数低于正常F1,而在成蟹阶段的平均蜕壳次数高于正常F1;(4)早熟F1腹脐覆盖腹甲宽度比例一直高于正常F1,但二者无显著差异(P0.05);(5)无论雌体还是雄体,早熟F1和正常F1的性腺指数和肝胰腺指数均无显著差异,单养条件下性腺均可发育成熟(P0.05)。综上,单养条件下,中华绒螯蟹早熟F1和正常F1的生长模式存在显著差异,两者都可以完成生殖蜕壳和性腺发育成熟,这为今后深入研究中华绒螯蟹个体生物学提供了理论依据和参考资料。

The Comparative Study on Growth Characteristics of Offspring from One-year Precocious and Two-year Normally Mature Chinese Mitten Crab (Eriocheir sinensis)

The difference of growth performance between one-year precious crabs Chinese Mitten Crab (Eridcheir sinensis) and two-year normally mature crabs has been remained unclear.Therefore,we compare the growth performance,coverage ratio of venter,gonadosomatic index (GSI) and hepatosomatic index (HSI) between one-year precious crabs (PF) and two-year normally mature crabs (NF) through monoculture in this study.The results showed that:(1) The individuals of PF were weighed more heavy than the individuals of NF significantly during 1st-2nd and 7th-8th molts for males (P ＜ 0.05),while for the females the body weight difference showed a significant difference between crabs of PF and NF during 1 st-5th and 7th molts (P ＜ 0.05,Fig.2),crabs of PF were more heavy;(2) The carapace length and carapace width of PF individuals were larger than NF individuals for both females and males with no significant difference (Fig.3,Fig.4);(3) In term of weight gain rate (WGR) and specific growth rate (SGR),PF individuals possessed higher WGR after 1st-2nd molts but lower WGR after 3rd-8th molts;a downward trend were showed in the SGR of the two families during the juvenile crab culture stage,and NF individuals were higher than PF individuals with significant differences during 3rd-4th molts for both males and females (P ＜ 0.05,Fig.5,Fig.6);(4) The PF individuals possessed longer interval during the 1st-5th molts but shorter interval during 6th-8th molts than NF individuals (Fig.7);(5) The lower molting frequency in juvenile crab culture stage and higher molting frequency in adult crab culture stage of PF individuals (Fig.8,Fig.9);(6) In terms of the coverage ratio of venter by sternite,PF individuals was always higher than NF individual with no significance difference (P ＞ 0.05,Fig.10);(7) For both males and females,no significant difference were observed on the GSI and HSI between FP and NP individuals after their puberty molting (P ＞ 0.05) (Fig.11).In conclusion,both PF and NF individuals could complete puberty molting and gonadal development through monoculture with significant difference existed on the growth patterns between them,this would provide theoretical foundation and reference material for further study on the individual biology ofE.sinensis.